The present invention relates to a seatbelt device of a vehicle, particularly to the seatbelt device in which pre-tensioner mechanisms provided for a driver's seat and another passenger's seat are operated when the vehicle is in a state, such as a spin or lateral slip, and when a DSC to stabilize a vehicle turning state operates during a vehicle turning.
Conventionally, in the seatbelt device of a vehicle equipped with the pre-tensioner mechanism, when the vehicle crash has been detected in advance by the crash pre-detecting sensor comprised of a millimeter-wave radar, based on the relative speed or relative distance with respect to an obstacle, such as the vehicle running in front, the pre-tensioner mechanism operates to wind up a specified amount of the webbing, so that the specified tension can be applied to the webbing and thereby the passenger's restraint can be improved. Then, when it is determined the vehicle dangerous state of crash has been avoided, the pre-tensioner mechanism equipped with an electric motor is driven reversely, so that the webbing is withdrawn by a specified amount and thereby the tension thereof returns to the previous tension before the webbing winding up. Thus, the unpleasant feeling of too much restraint of the webbing can be lessened.
Also, passengers tend to be moved forward due to the inertia at the vehicle braking, and they tend to be moved laterally at the vehicle turning. Accordingly, increasing the webbing tension and thereby improving the passenger's restraint will be necessary in these cases. Thus, the seatbelt device performing such functions is also known. For example, U.S. Patent Application Publication No. 2003/0209900 A1 discloses the device in which there are provided the lateral acceleration sensor and the longitudinal acceleration sensor, and it is determined based on these sensors whether the vehicle is in the braking state or in the turning state. Herein, when it has been determined that the vehicle is in the braking state, the pre-tensioner mechanism operates so that the tension of the webbing of the assistant's seat can be higher than that of the webbing of the driver's seat. While, when it has been determined that the vehicle is in the turning state, the pre-tensioner mechanism operates so that the tension of the webbing of the driver's seat can be higher than that of the webbing of the assistant's seat. Thereby, the tension of the webbing can be properly applied to the passenger according to the vehicle traveling state, and thus the proper restraint can be provided to the passenger without giving any unpleasant feelings.
Meanwhile, vehicles equipped with DSC (Dynamic Stability Control) have increased recently. The DSC can stabilize the vehicle traveling state by controlling the engine brake and the braking forces of four brakes when it has been detected that the vehicle travels on a slippery road or turns at a high speed and thereby the vehicle is in the dangerous state of spin or lateral slip. Herein, it is desired to provide the seatbelt device to operate the pre-tensioner mechanism additionally according to the operation of the DSC in order to further improve the safety of passengers.